(#1412) E2E - Add test case for path+URL construction in CLI

Overview
--------

In #1412, the regression involved CLI processes producing incorrect URLs.
This adds some test-coverage.

Before
------

No test coverage for URLs in CLI environment.

After
-----

There is some test-coverage. It's able to reveal the existence of the bug from 1412.

Comments
--------

A lot of path/URL construction is dependent on the environment/site-build.
The test does not, on its own, guarantee that all environments work.
Rather, it adds a new slice of cheese to the stack.

This slice is moderately generic - in that I've successfully tested it
localy on `drupal-demo` and `wp-demo` builds.  In theory, it should work on
other build types (as long as they set variables `CIVI_CORE`, `CMS_ROOT`,
`CMS_URL`).

tests/phpunit/E2E/Extern/CliRunnerTest.php

+<?php
+/*
+ +--------------------------------------------------------------------+
+ | CiviCRM version 5                                                  |
+ +--------------------------------------------------------------------+
+ | Copyright CiviCRM LLC (c) 2004-2019                                |
+ +--------------------------------------------------------------------+
+ | This file is a part of CiviCRM.                                    |
+ |                                                                    |
+ | CiviCRM is free software; you can copy, modify, and distribute it  |
+ | under the terms of the GNU Affero General Public License           |
+ | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
+ |                                                                    |
+ | CiviCRM is distributed in the hope that it will be useful, but     |
+ | WITHOUT ANY WARRANTY; without even the implied warranty of         |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
+ | See the GNU Affero General Public License for more details.        |
+ |                                                                    |
+ | You should have received a copy of the GNU Affero General Public   |
+ | License along with this program; if not, contact CiviCRM LLC       |
+ | at info[AT]civicrm[DOT]org. If you have questions about the        |
+ | GNU Affero General Public License or the licensing of CiviCRM,     |
+ | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
+ +--------------------------------------------------------------------+
+ */
+
+/**
+ * Check that various CLI runners are able to bootstrap an environment with
+ * reasonable paths.
+ *
+ * This test assumes that you have built with "civibuild" (or configured cv.json)
+ * to provide canonical/expected values.
+ *
+ * It then executes the any supported CLI tools (cv, drush, wp) and checks if
+ * their output matches the expected value.
+ *
+ * @group e2e
+ */
+class E2E_Extern_CliRunnerTest extends CiviEndToEndTestCase {
+
+  protected function setUp() {
+    parent::setUp();
+
+    foreach (['CIVI_CORE', 'CMS_ROOT', 'CMS_URL'] as $var) {
+      if (empty($GLOBALS['_CV'][$var])) {
+        $this->markTestSkipped("Test environment does provide the civibuild/cv variable ($var)");
+      }
+    }
+  }
+
+  protected function tearDown() {
+    parent::tearDown();
+  }
+
+  /**
+   * @return array
+   *   Each case gives a name (eg "cv") and template for executing the command
+   *   (eg "cv ev @PHP").
+   */
+  public function getRunners() {
+    $cliRunners = [];
+
+    if (CIVICRM_UF === 'WordPress') {
+      $cliRunners['wp'] = ['wp', 'wp eval \'civicrm_initialize();\'@PHP'];
+    }
+    if (CIVICRM_UF === 'Drupal' || CIVICRM_UF === 'Backdrop') {
+      $cliRunners['drush'] = ['drush', 'drush ev \'civicrm_initialize();\'@PHP'];
+    }
+    // TODO: Drupal8 w/drush (doesn't use civicrm_initialize?)
+
+    $cliRunners['cv'] = ['cv', 'cv ev @PHP'];
+
+    return $cliRunners;
+  }
+
+  public function getRunnersAndPaths() {
+    $exs = [];
+    foreach ($this->getRunners() as $runner) {
+      $exs[] = array_merge($runner, ['[civicrm.root]/css/civicrm.css']);
+      $exs[] = array_merge($runner, ['[civicrm.packages]/jquery/css/images/arrow.png']);
+    }
+    return $exs;
+  }
+
+  /**
+   * @param string $name
+   *   The name of the command we're testing with.
+   *   Ex: 'cv'
+   * @param string $r
+   *   Ex: 'cv ev @PHP'
+   * @dataProvider getRunners
+   */
+  public function testBasicPathUrl($name, $r) {
+    $this->assertNotEmpty($this->findCommand($name), 'The command "$name" does not appear in the PATH.');
+
+    $cv = $GLOBALS['_CV'];
+    $this->assertEquals($cv['CIVI_CORE'], $this->callRunnerJson($r, '$GLOBALS[\'civicrm_root\']'));
+    $this->assertEquals($cv['CMS_URL'] . 'foo', $this->callRunnerJson($r, 'Civi::paths()->getUrl(\'[cms.root]/foo\')'));
+    $this->assertEquals($cv['CMS_ROOT'] . 'foo', $this->callRunnerJson($r, 'Civi::paths()->getPath(\'[cms.root]/foo\')'));
+    $this->assertEquals($cv['CIVI_CORE'] . 'css/civicrm.css', $this->callRunnerJson($r, 'Civi::paths()->getPath(\'[civicrm.root]/css/civicrm.css\')'));
+
+    $ufrUrl = $this->callRunnerJson($r, 'CRM_Core_Config::singleton()->userFrameworkResourceURL');
+    $crmUrl = $this->callRunnerJson($r, 'Civi::paths()->getUrl("[civicrm.root]/.")');
+    $this->assertEquals($crmUrl, $ufrUrl);
+  }
+
+  /**
+   * For some URLs, we don't have a good environment variable for predicting the URL.
+   * Instead, we'll just see if the generated URLs match the generated paths.
+   *
+   * @param string $name
+   *   The name of the command we're testing with.
+   *   Ex: 'cv'
+   * @param string $r
+   *   Ex: 'cv ev @PHP'
+   * @param string $fileExpr
+   *   Ex: '[civicrm.root]/LICENSE'
+   * @dataProvider getRunnersAndPaths
+   */
+  public function testPathUrlMatch($name, $r, $fileExpr) {
+    $this->assertNotEmpty($this->findCommand($name), 'The command "$name" does not appear in the PATH.');
+    $localPath = $this->callRunnerJson($r, "Civi::paths()->getPath('$fileExpr')");
+    $remoteUrl = $this->callRunnerJson($r, "Civi::paths()->getUrl('$fileExpr')");
+    $this->assertFileExists($localPath);
+    $localContent = file_get_contents($localPath);
+    $this->assertNotEmpty($localContent);
+    $this->assertEquals($localContent, file_get_contents($remoteUrl),
+      "civicrm.css should yield same content via local path ($localPath) or HTTP URL ($remoteUrl)"
+    );
+  }
+
+  /**
+   * @param string $runner
+   *   Ex: 'cv ev @PHP'
+   * @param string $phpExpr
+   *   PHP expression to evaluate and return. (Encoded+decoded as JSON)
+   * @return mixed
+   *   The result of running $phpExpr through the given $runner.
+   */
+  protected function callRunnerJson($runner, $phpExpr) {
+    $json = $this->callRunnerOk($runner, "echo json_encode($phpExpr);");
+    return json_decode($json);
+  }
+
+  /**
+   * @param string $runner
+   *   Ex: 'cv ev @PHP'
+   * @param string $phpStmt
+   *   PHP code to execute
+   * @return string
+   *   The console output of running $phpStmt through the given $runner.
+   */
+  protected function callRunnerOk($runner, $phpStmt) {
+    $cmd = strtr($runner, ['@PHP' => escapeshellarg($phpStmt)]);
+    exec($cmd, $output, $val);
+    $this->assertEquals(0, $val, "Command returned error ($cmd) ($val)");
+    return implode("", $output);
+  }
+
+  protected function findCommand($name) {
+    $paths = explode(PATH_SEPARATOR, getenv('PATH'));
+    foreach ($paths as $path) {
+      if (file_exists("$path/$name")) {
+        return "$path/$name";
+      }
+    }
+    return NULL;
+  }
+
+}